Ofcom continued: “Broadcasters inviting viewers to vote using premium rate numbers have a particular responsibility to ensure the audience is clear about what they are voting for.

“By failing to do so, we’ve concluded the presentation of the act was likely to have materially misled some people.”

ITV said in a statement: “The Britain’s Got Talent production team apologised at the time for not making it clearer to the judges and viewers at home that three dogs were involved in the final performance.

“There was never any intention to mislead viewers and in their decision Ofcom said they ‘have no reason to believe that there was any intention to deceive viewers that the tightrope walk actually involved a second dog’.”

Following this, it went on to say: “The majority of votes cast for Jules’ act were received through the free voting app.

“However, we accept that some viewers who voted for the winning act by a paid voting route may wish to seek a refund, or that the cost of their vote be donated in full to the Royal Variety charity.

“Details about how to obtain a refund, or to request that a refund be donated to the charity, are now on our website.”

A message on the ITV website, regarding the refund, said: “For avoidance of doubt, viewers who voted by a paid route for any other act in the final of BGT 2015 (ie other than the winning act) are not eligible for a refund or to request donation of a refund.”

More than 13 million viewers watched O’Dwyer and Matisse become the second dog act to win Britain’s Got Talent - following Ashleigh Butler and Pudsey in 2012 - in the highest-rated final since that year.

Voting figures showed that they won by just 2% - getting 22.6% of votes compared with 20.4% for magician Raven.